Steel Can Be Worked Cold

As noted above, steel can be worked cold,
as in the case of cold-rolled steel. Heat treatment of cold-worked
steel is a very delicate operation. Cold working hardens and strengthens
steel. It also introduces internal stresses. Heat-treatments are
designed to eliminate the stresses without losing the hardness
and strength. This is done by tempering at a low heat. Avoid the
blue range (350 to 750 deg.C.). Tempering for a considerable time just
under the critical is liable to cause great brittleness. Annealing
(reheating through the critical) destroys the effect of cold work.